US3240877A - Stabilizing unstable synchronizing phase positions in receivers of synchronously operating telegraph systems - Google Patents

Stabilizing unstable synchronizing phase positions in receivers of synchronously operating telegraph systems Download PDF

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Publication number
US3240877A
US3240877A US135551A US13555161A US3240877A US 3240877 A US3240877 A US 3240877A US 135551 A US135551 A US 135551A US 13555161 A US13555161 A US 13555161A US 3240877 A US3240877 A US 3240877A
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Prior art keywords
voltage
synchronizing
phase
alternating
line
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US135551A
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English (en)
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Rudolph Hans
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Siemens and Halske AG
Siemens Corp
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Siemens Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B21/00—Generation of oscillations by combining unmodulated signals of different frequencies
    • H03B21/01—Generation of oscillations by combining unmodulated signals of different frequencies by beating unmodulated signals of different frequencies
    • H03B21/02—Generation of oscillations by combining unmodulated signals of different frequencies by beating unmodulated signals of different frequencies by plural beating, i.e. for frequency synthesis ; Beating in combination with multiplication or division of frequency
    • H03B21/025—Generation of oscillations by combining unmodulated signals of different frequencies by beating unmodulated signals of different frequencies by plural beating, i.e. for frequency synthesis ; Beating in combination with multiplication or division of frequency by repeated mixing in combination with division of frequency only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
    • H04L7/033—Speed or phase control by the received code signals, the signals containing no special synchronisation information using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop

Definitions

  • This invention is concerned with a method of and a circuit arrangement for stabilizing unstable synchronizing phase positions in receivers of synchronously operating telegraph systems.
  • FIG. 1 shows the relative course of impulses occurring in a known synchronizing system to aid in explaining the drawbacks thereof;
  • FIG. 2 illustrates a phase comparison device
  • FIG. 3 represents a first advantageous embodiment of the invention
  • FIG. 4 shows a second embodiment
  • FIG. 5 indicates the course of impulses to be considered in connection with the invention.
  • FIG. 6 illustrates a modification of the embodiment illustrated in FIG. 3.
  • the transmitter and the receiver devices In a synchronously operating telegraph system, the transmitter and the receiver devices must operate in synchronism as to frequency and phase so as to permit at the receiver correct evaluation of the transmitted telegraph symbols. It is for this purpose necessary to transmit synchronizing signals incident to the transmission of messages or to derive such signals from the received telegraph symbols.
  • the phase comparison is carried out, for example, with the aid of a device indicated in FIG. 2.
  • the switch S which may be an electronic switch is for simplification shown as a mechanical switch, is always briefly closed for the duration of a synchronizing impulse.
  • the rectangular voltage is conducted to the input E.
  • the closure time of the switch S which in the case of correct phase position of the receiver distributor substantially coincides with the rising flank of the rectangular voltage, there will first flow a negative and thereafter a positive current over the resistor R to the capacitor C. Accordingly, averaged over an extended interval, there will not be produced a charge on the capacitor C.
  • a positive voltage is in the case of a lagging phase error in similar manner formed at the capacitor C, such voltage accumulating and, upon reaching the energizing value of a control member, causing such member to etfect a synchronizing operation in opposite direction.
  • phase error is considerable, which might happen particularly upon starting the operation of a system, it will be necessary to apply for the correction thereof a plurality of successive identically directed synchronizing operations.
  • the object of the present invention is to avoid these drawbacks, that is, the unstable synchronizing phases which are as such permissible, shall be stabilized, so as to avoid the prolonged synchronizing operations resulting upon disruption of the unstable synchronizing phase position.
  • this object is realized by effecting the regulation of the operation or rotation phase in the direction of the synchronizing phase which is nearest to the momentarily present phase position.
  • the regulation voltages for the regulation of the rotation phase position of the receiver device are derived from the comparison of synchronizing impulses occurring periodically with twice the telegraph element spacing, with an alternating reference voltage which is rigidly in phase with the rotation of the receiver device and the period of which is equal to the spacing of the synchronizing impulses, and wherein respectively a stable or a further unstable synchronizing phase of the alternating reference voltage and therewith of the rotation phase of the receiver device, at which no regulation voltages appear, is present when the zero passages of the alternating reference voltage are in one direction effected exactly in the center of the synchronizing impulses, while there occur, responsive to deviations, regulation voltages of different polarity which effect a regulation in the direction of the stable synchronizing phase position, the regulation voltage or the alternating reference voltage is for this purpose changed in polarity when the spacing of the synchronizing impulses from the unstable synchronizing phase position is smaller than the spacing thereof from the stable synchronizing phase position.
  • a first regulation voltage for the regulation of the synchronizing phase of the receiver device is obtained by comparing, as to phase and frequency, a transmitted alternating synchronizing voltage with an alternating reference voltage of the same frequency, which is rigidly in phase with the rotation of the receiver device, and wherein there occur in two phase positions which differ by 180, a stable and an unstable synchronizing phase position at which no regulation voltages appear
  • the stabilizat-ion of the unstable synchronizing phase is obtained by comparison of an alternating voltage which is phase shifted, preferably by 90, with respect to the alternating refrence voltage, with the alternating synchronizing voltage, thereby obtaining a second regulation voltage which is responsive to changing polarity effective to change the polarity of the first regulation voltage.
  • FIG. 3 shows a first advantageous embodiment of the invention
  • the received alternating synchronizing voltage according to FIG. 1 is conducted to the input E of the amplifier V for suitable amplification thereof.
  • the flanks are differentiated in a differentiating member D to form the positive impulses represented in line e) of FIG. 1.
  • These impulses actuate the relay R which closes its contacts r1 and r2 for the duration of the respective impulses.
  • the rectangular alternating voltage with a frequency corresponding to that of the alternating synchronizing voltage which is conducted to the input E, which is required for the phase comparison, is derived from the quartz controlled highly constant oscillator Q.
  • the frequency divider stages T1 and T2 divide the oscillator frequency as required to produce the necessary alternating rectangular voltage.
  • the output voltage of the frequency divider T2 is indicated in line it) of FIG. 1. If required, a small phase correction may be effected in the phase shifter P. In the case. of correct rotation phase position of the receiver device, two complementary rectangular voltages indicated in FIG. 1, lines f) and g), will appear at the output of the phase shifter P.
  • the negative charge will accordingly predominate in the capacitor C1 while the positive charge will predominate in the capacitor C2.
  • the positive charge on the capacitor C2 reaches the energizing value of the control member S2, the latter will become operative to affect the frequency divider T1 such, for example, that the division ratio thereof is for a short interval increased.
  • the frequency divider T1 such, for example, that the division ratio thereof is for a short interval increased.
  • the capacitor C1 will accumulate a positive charge and the capacitor C2, a negative charge.
  • the control member S1 Upon exceeding the threshold value, the control member S1 will operatively energize and will cause the frequency divider T1 to temporarily reduce its normal division ratio, thereby effecting the shifting of the phase position of the rectangular voltages, FIG. 1, lines and g) somewhat to the right.
  • the capacitors C1 and C2 are discharged after each phase correction.
  • the capacitor C1 would be during the closure time of the contact r1 affected by a rectangular voltage with the phase position according to line g) of FIG. 1, while the capacitor C2 would be affected over the contact r2 by the phase position according to line of FIG. 1. No charging of the capacitors C1 and C2 would be effected by averaging at this phase position. However, if this phase position should be shifted to the right, for example, responsive to some disturbance, there would accumulate a positive voltage on the capacitor C1 and a negative voltage on the capacitor C2. Upon exceeding the threshold value, the control member S1 would energize and effect in the previously described manner a further shifting of the rectangular voltage to the right. These phase corrections would be continued until stable rotation phase is ob tained which is shifted by one element length.
  • a ring modulator M In order to avoid these regulation operations from the unstable to the stable synchronizing phase position, there is provided a ring modulator M and the pole changing device U controlled thereby.
  • To the left input of the ring modulator M is conducted the alternating synchronizing voltage of line a) of FIG. 1 and to the right input thereof is conducted the alternating reference voltage from the frequency divider T2, represented in line h) of FIG. 1. Since these voltages are initially in phase there will appear at the output of the ring modulator M a positive direct voltage represented in line i) in FIG. 1,
  • the rectangular voltage supplied by the frequency divider T2 will be in opposing phase with respect to the alternating synchronizing voltage conducted to the input E.
  • the output voltage of the ring modulator M is in such case negative, see last line I) of FIG. 1, and the relay U places its contacts a1 and 112 into alternate positions.
  • This effects a pole changing of the rectangular voltages conducted to the capacitors C1 and C2, so that a rectangular voltage according to line 7), FIG. 1, is again conducted to the capacitor C1 while a rectangular voltage according to line g) of FIG. 1 is conducted to the capacitor C2.
  • the change of polarity accordingly secures the stability of the synchronization even with respect to the previously unstable synchronizing phase.
  • the rectangular voltage given off from the frequency divider T2 will be phase shifted by 90 with respect to the alternating synchronizing voltage.
  • the ring modulator M will in this case not deliver a direct voltage.
  • the operation of the pole changing device U is such that it can be only in one or the other position; it remains in the position in which it happens to be and thereby determines the direction in which the synchronization is to take place. Accordingly, an unstable condition is excluded.
  • FIG. 4 shows a second advantageous embodiment of the invention.
  • the highly constant oscillator Q produces an alternating voltage which passes through the adjustable phase shifter Ph to the frequency divider T1 in which it is divided to form the frequency 2f.
  • From the frequency divider T1 are taken two voltages of opposite phase, that is, voltages of the frequency 1 which are phase shifted by 180 and these voltages are conducted to two frequency reducers T2 and T3 in which the frequency is reduced to one-half, thereby also reducing the phase angle difference to one-half, that is, to 90.
  • the coupling between the two frequency dividers T2 and T3 assures that the phase position of the two voltages which had been divided to the frequencies f are in mutually fixed relationship. Accordingly, the rectangular voltages given off from the frequency dividers T2 and T3 are mutually phase shifted by 90.
  • the incoming alternating synchronizing voltage, indicated in line a) of FIG. 5, is conducted to the input E (FIG. 4).
  • Such voltage is amplified in the amplifier V and conducted to the two left inputs of the ring modulators M1 and M2.
  • To the other inputs of these modulators are conducted the output voltages of the frequency dividers T2 and T3, respectively.
  • the direct voltage part given 01f by the modulators is proportional to the cosine of the phase angle difference between the two alternating voltages conducted thereto.
  • the modulator M1 will receive from the frequency divider T2 a rectangular voltage according to line b) of FIG. 5.
  • the phase angle difference with respect to the alternating synchronizing voltage according to line a), FIG. 5, amounts thereby to 90, and the voltage given off from the modulator M1 does not contain a direct voltage part according to line c) of FIG. 5.
  • the alternating voltage part of the output voltage of the modulator M1 which is extended over the pole changing contacts a1 and a2, is eliminated in a filter member comprising the resistors R1 and R2 and the capacitor C, and the control amplifier S therefore does not receive any voltage.
  • control amplifier S is suitable for amplifying voltages of any desired polarity and that its output voltage, which may be present, serves for driving a motor M which is '6 operative for adjusting of regulating the phase shifter Ph, thereby equalizing a phase error.
  • control amplifier S will not receive any regulation voltage if the rotation phase of the receiver device is with respect to the alternating synchronizing voltage shifted by the amount of one whole element.
  • the rotation phase position of the receiver device is thus held stable in thissecond correct phase position.
  • FIG. 5 also shows in lines k) to n) the conditions resulting in the case of a phase error in the amount of onehalf of an element
  • the course of the output voltage of the frequency divider T2 then corresponds to that shown in line k) and is in phase with the alternating synchronizing voltage according to line a) in FIG. 5.
  • At the output of the modulator M1 appears the maximum positive regulation voltage.
  • the phase must now in any case be readjusted by 90 by the operation of the motor M. It is immaterial whether the phase is thereby advanced or retarded by this amount.
  • the direction in which the adjustment is effected depends upon the positions in which the contacts a1 and a2 happen to be, the relay U which controls these contacts being in such case without current, since it does not receive any voltage from the modulator M2 owing to the fact that the alternating synchronization voltage (line a) in FIG. 5) is by 90 displaced with respect to the voltage (line m) in FIG. 5) which is given off by the frequency divider T3.
  • a stabilization of the unstable synchronization phase position could in case of a phase displacement by an amount greater than half an element length, also be obtained by pole-changing the regulating voltage or the received alternating synchronization voltage instead of pole-changing the alternating reference voltage.
  • FIG. 6 illustrates a circuit which, with the exception of the pole changing circuit, is identical with that of FIG. 3. In FIG. 6, however, the polarity of the regulating voltage is changed instead of the alternating reference voltage.
  • the embodiments disclosed herein can be constructed substantially wholly electronically, that is, for example, the relays shown in the drawings and contacts controlled thereby can be replaced by functionall equivalent electronic devices.
  • a circuit arrangement for stabilizing unstable synchronizing phases at the receiver devices of synchronously operating telegraph systems comprising a modulator for receiving an alternating reference voltage and an alternating synchronizing voltage of identical frequency, a testing device, a pole changing device controlled by the output voltage of said modulator in accordance with the polarity of said output voltage for conducting to said testing device the alternating reference voltage and a voltage complementary thereto, and means for totalling up the currents and voltages respectively conducted thereto incident to and for the duration of synchronizing impulses derived from the alternating synchronizing voltage and elfecting upon exceeding a minimum value alteration of the phase position of the alternating reference voltage in one or the other direction.
  • a circuit arrangement according to claim 1, comprising switching means in said testing device which are closed for the duration of the respective synchronizing signals, and an RC-voltage divider cooperating with the respective switching means for receiving thereover the alternating reference voltage and the voltage complementary thereto which are extended over said pole changing devices.
  • a circuit arrangement according to claim 2 comprising a switch cooperating with each RC-voltage divider, said switch energizing responsive to a voltage on the corresponding capacitor which exceeds a predetermined value and thereby altering the phase position of the alternating reference voltage.
  • a circuit arrangement for stabilizing unstable synchronizing phases at the receiver devices of synchronously operating telegraph systems comprising two modulators for receiving an alternating synchronizing voltage and respectively the alternating reference voltage in which the reference alternating voltage fed to the first modulator is phase shifted by 90 with respect to the reference alternating voltage fed to the second modulator, the output voltage of one of said modulators controlling depending upon the polarity, a pole changing device for the regulation voltage delivered by the other modulator.
  • a circuit arrangement for stabilizing unstable synchronizing phases at the receiver devices of synchronously operating telegraph systems comprising means for supplying an alternating reference voltage of identical frequency with the alternating synchronizing voltage of the received signals, means responsive to a regulating voltage for varying the phase of said alternating reference voltage, means for comparing said alternating synchronizing voltage with said reference voltage and a voltage complementary to the latter, operative to derive a regulating voltage which is applied to said phase varying means, and means operatively connected to the source of said alternating reference and synchronizing voltages operative to determine the polarity of the regulating voltage whereby the phase regulation takes place in the direction of the synchronizing phase position which is nearest to the momentarily present phase position.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
  • Dc Digital Transmission (AREA)
US135551A 1960-09-07 1961-09-01 Stabilizing unstable synchronizing phase positions in receivers of synchronously operating telegraph systems Expired - Lifetime US3240877A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES70246A DE1128460B (de) 1960-09-07 1960-09-07 Verfahren und Schaltungsanordnung zum Aufrechterhalten des Gleichlaufs der Sende- und Empfangseinrichtungen in Synchron-Telegrafieranlagen

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US3240877A true US3240877A (en) 1966-03-15

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US135551A Expired - Lifetime US3240877A (en) 1960-09-07 1961-09-01 Stabilizing unstable synchronizing phase positions in receivers of synchronously operating telegraph systems

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US (1) US3240877A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS4929762B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BE (1) BE607914A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CH (1) CH394287A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE1128460B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB938876A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL142034B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

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Publication number Priority date Publication date Assignee Title
GB1052485A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1963-06-25
CH447322A (de) * 1966-04-07 1967-11-30 Bbc Brown Boveri & Cie Verfahren und Einrichtung zur Taktsynchronisierung, insbesondere für Fernwirkanlagen
JPS5398180U (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1977-01-11 1978-08-09

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2843669A (en) * 1953-10-27 1958-07-15 Philips Corp Synchronized generator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2843669A (en) * 1953-10-27 1958-07-15 Philips Corp Synchronized generator

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JPS4929762B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-08-07
NL142034B (nl) 1974-04-16
BE607914A (fr) 1962-01-02
DE1128460B (de) 1962-04-26
GB938876A (en) 1963-10-09
CH394287A (de) 1965-06-30
NL268962A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1964-06-25

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